1. Technical Field
The invention relates to the tracking and monitoring of an object. More particularly, the invention relates to an apparatus and to a family of methods that gather information on the location and transportation of an object, and that makes shipping decisions, independent of human input.
2. Description of the Prior Art
The tracking of shipping has increased over the years. As objects in transit move from place to place through, ships, planes, and trucks, carriers have sought to increase customer satisfaction by providing in-transit information. For example, Federal Express uses a bar code system in which a bar code is added to each shipped object. Each object is scanned at several points throughout its delivery trip. The scanned information is accessible to a customer through a customer service agent or through the Internet. One problem with this method of shipping is that the customer has no information regarding the object while it is in transit. All the information the customer can receive, is information regarding where the object has been scanned last. This information provides the customer with no insights to future events, such as whether the object will arrive on time. Furthermore, the customer has no method of intervening in the shipping process, such as changing for example the mode of shipping or upgrade the service level to expedited service to make up for lost time.
What is needed is a system, which uses the tracking information by for example monitoring the schedule and progress of an object in transit, and a system that can take in addition proactive actions based on that information such as for example making upgrades in service level to the shipping if the object is behind schedule.
Generally, the art of radio data communication and radio tracking is extensive. The most widely used system for position determination is presently the Loran-C System, established by the U.S. Coast Guard more than twenty years ago, for navigation on inland and coastal waters of the U.S.A. A Loran-C receiver simultaneously processes the signals received from a number of Loran-C broadcast stations, and determines its local coordinates from phase comparisons between the various signals and from (internal) tables of the known position of the signal sources. Loran-C offers a position uncertainty of about ⅙ mile in open areas and over water. The most significant deficiency of the Loran system is that it provides no communication path for voice or data message information.
Satellite-based systems providing a service similar to Loran-C are now in operation, such as the military and commercial versions of Global Positioning Satellite system (GPS). Such systems can provide accurate position determination (about a 50 m error for the commercial version of GPS) from signal received simultaneously from at least three high-orbiting satellites. In many respects, the GPS system works as a “Loran-C-in-the-sky,” and performs well in open areas, but often does not work well in many consumer applications, and in urban areas. This is because the power levels from the satellites are very low and the mobile transponder requires a clear, direct view of the satellites for its operation. Moreover, the cost of commercial GPS and Loran-C receivers is excessive and there is no means by which the location of a positioned object can be communicated beyond the object itself.
Another position determining system is the Signpost system. The resolution of this system is the spacing between signposts, and the position is recorded as the vehicle passes the signpost. Unfortunately, the position of the vehicle between posts is unknown.
An interesting commercial version of a signpost system, developed by Amtech Corporation of Dallas, Tex., uses passive, coded tags, capable of being “scanned” by a locally strong RF signal at the signpost. Commercial versions of this system are used to keep track of the passive-responding “Toll-Tags” attached to automobiles and railroad cars. Toll-Tags have also been used for automatic toll-road fee collection.
Two other vehicle locating systems worth mentioning include the North American Teletrac (manufactured by the Teletrac Inc. of Vista, Calif.) and the Lo-jack (manufactured by the LoJack Corporation of Dedham, Mass.) vehicle recovery systems. The Teletrac system uses a high frequency paging channel to activate a homing transponder on the vehicle being tracked. The transponder transmits a repeated spread-spectrum sequence, which a network of base stations receive, and from the difference in the delay between the sequence received at pairs of base stations the system determine the differences in the signal propagation flight time. From these differences a position fix can be determined by hyperbolic multilateration.
The capacity of the Teletrac system is limited to approximately 35 position fixes per second, and the system has little or no capacity to convey user information to the mobile location or back to the system.
The Lo-jack system uses a paging channel to activate a homing device installed on a stolen vehicle. Once the vehicle operator informs the recovery service of the loss of the vehicle, the paging channel is used to activate the homing transmitter, which emits a user ID-code on its homing carrier. Police tracking vehicles, equipped with special Doppler direction finding receivers, then locate the vehicle by monitoring a combination of signal-strength and direction readings of the identified carrier being received.
A number of private data-networks have recently been built to provide mobile radio data communications. Early systems have been extensions of prior voice radio systems with analog modems included in the link to provide data transmission and reception. With the advent of Specialized Mobile Radio (SMR) and the birth of Cellular Radio Telephones (which is a particular implementation of SMR), full duplex data connections became possible. These implementations, unfortunately, have been based on the current technology of voice-radio channels, which limit the capacity of the channel to practical data transmission rates in the range of 1,200 to 19,200 baud, with 2,400 to 4,800 baud being typical, depending on link budget and equipment cost.
Several private and public radio data networks have been built along these lines by Ericsson, Motorola, and others. Data-modems have recently become available from several manufacturers to operate with cellular radio telephone systems and provide typical data rates of 2,400 baud.
Some satellite-based mobile data communications have been established in the Mobile Satellite Service (MSS), and companies such a Geostar, Qualcomm, and Hughes have offered the service to primarily long-distance trucking companies to allow them to stay in contact with their cross-country fleets. A mobile data communication link is often combined with a Loran-C navigational system to report the approximate location of the vehicle.
What is needed is a system which links all the aforementioned systems and applies logical and hierarchical rules to derive a location of a tracked item, so that the most accurate of tracking information is available. Also needed is a system which can provide relational information between an object and its transportation means so that a user knows whether an object is actually on the transportation means or not. Further, it would be advantageous to provide a system that collects all available information concerning an item in transit and that “mines” such information to determine, for example, whether an item that forms part of a coordinated, multipart shipment is due to arrive with all other parts of the shipment, or if any actions must be taken to meet a particular delivery commitment, or to protect items in transit, for example, from environmental extremes, Furthermore what is needed is a system, that takes the tracking information and relates it to other information, such as a planned schedule, and draws based on the deviation of planned versus actual conclusions. Finally, what is also needed is that such a system evaluates the carriers based on their performance, as actual performance is measured against planned performance.